> I personally am fluent in only one language (because I'm an American ;-7),
> so all of my web pages have been in a single language. I wonder, aside
> perhaps from character set configuration, what reasons there are for
> defining the language of a block of text?

.. well, it might be useful for automated resource discovery, search
engines with thesauri, etc. etc. - so that if you were in an "en-gb" block
pavement == footpath, while in an "en-us" block pavement == roadway,
or setting up speech synthesis systems, etc.

... I'm not sure whether CSS addresses things that might change between
languages, such as number representation, hyphenation, quotations, braces
etc., but it might be useful to define alternate style sheets for each
language used on a page ...